{"id":"CVE-2021-43839","aliases":["GHSA-f854-hpxv-cw9r"],"url":"https://o3.security/vulnerability/CVE-2021-43839","summary":"Drainage of FeeCollector's Block Transaction Fees in cronos","details":"### Impact\nIn Cronos nodes running versions before v0.6.5, it is possible to take transaction fees from Cosmos SDK's FeeCollector for the current block by sending a custom crafted MsgEthereumTx.\n\nUser funds and balances are safe.\n\n\n### Patches\nThis problem has been patched in Cronos v0.6.5 on the mempool level.\nThe next network upgrade with consensus-breaking changes will patch it on the consensus level.\n\n### Workarounds\nThere are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience.\n\n### Credits\nThank you to @zb3 for reporting this issue on [Cronos Immunefi Bug Bounty Program](https://immunefi.com/bounty/cronos/), to @cyril-crypto for reproducing the issue and to @yihuang and @thomas-nguy for patching the issue on the CheckTx (mempool) and the DeliverTx (consensus) levels.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open a discussion in [crypto-org-chain/cronos](https://github.com/crypto-org-chain/cronos/discussions/new)\n* Email us at [chain@crypto.org](mailto:chain@crypto.org)\n","published":"2021-12-21T17:15:08.413Z","modified":"2026-07-08T06:28:59.438939517Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"epss":{"score":0.01313,"percentile":0.68065,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/crypto-org-chain/cronos","fixedVersion":"0.6.5"},{"ecosystem":"Go","name":"github.com/tharsis/ethermint","fixedVersion":"0.10.0"},{"ecosystem":"Go","name":"github.com/tharsis/evmos","fixedVersion":null},{"ecosystem":"Go","name":"github.com/tharsis/ethermint","fixedVersion":"0.7.3"}],"fix":{"url":"https://github.com/crypto-org-chain/cronos/commit/150ef237b37ac28c8136e1c0f494932860b9ebe8","label":"crypto-org-chain/cronos@150ef23"},"references":[{"type":"ADVISORY","url":"https://github.com/crypto-org-chain/cronos/security/advisories/GHSA-f854-hpxv-cw9r"},{"type":"FIX","url":"https://github.com/crypto-org-chain/cronos/commit/150ef237b37ac28c8136e1c0f494932860b9ebe8"},{"type":"FIX","url":"https://github.com/crypto-org-chain/cronos/pull/270"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-43839"},{"type":"WEB","url":"https://github.com/crypto-org-chain/cronos"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T06:28:59.438939517Z"}}